This invention relates to the art of flaring low pressure hydrocarbon gases, smokelessly.
It is well known in the art that flaring of low pressure hydrocarbon gases having a molecular weight ratio of hydrogen to carbon less than 0.30 tends to produce smoke as a result of incomplete combustion and the formation of free carbon particles. The release of free carbon into the atmosphere creates a dark smoke plume which is unsightly and a matter of poor ecological practice. Various methods have been devised for coping with smoke generation. One method involves the introduction of a smoke suppressant, typically steam or water to the combustion zone. The water, in vapor phase, reacts with the hydrocarbon by familar and well known endothermal reactions. In some instances, the introduction of this suppressant also introduces air to assist in the complete combustion of the burning gases. Another method relates to the use of powered air for turbulent mixing of air with the hydrocarbon gas for more complete smokeless combustion.
There are instances in certain refineries, or process plants where neither steam or water or air powered turbulent mixing are available to smokelessly burn or flare low pressure hydrocarbon gases that are created as a part of the plant. The flaring of such gases is the only economical manner in which to handle these gases which must be removed from the system since they are not capable of being utilized elsewhere.
Wind is another problem with burning low pressure hydrocarbons above an elevated stack. If there is insufficient pressure to cause the flame to `stand-up` the flames will `lick` the side of the stack causing its destruction, besides the constant problem of maintaining ignition. Standing the flames upward is preferred.